/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2014 University of Manchester
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package uk.ac.manchester.cs.mekon.gui;

import javax.swing.*;

import uk.ac.manchester.cs.mekon.model.*;

import uk.ac.manchester.cs.mekon.gui.util.*;

/**
 * @author Colin Puleston
 */
class NavigationPanel extends JPanel {

	static private final long serialVersionUID = -1;

	static private final String BACKWARD_BUTTON_LABEL = "<";
	static private final String FORWARD_BUTTON_LABEL = ">";

	private ModelFrameSelections modelFrameSelections;

	private abstract class DirectionButton extends GButton {

		static private final long serialVersionUID = -1;

		private class EnablingUpdater extends CFrameSelectionListener {

			protected void onSelected(CFrame frame) {

				setEnabled(canGo());
			}
		}

		DirectionButton(String label) {

			super(label);

			setEnabled(false);

			modelFrameSelections.addSelectionListener(new EnablingUpdater());
		}

		abstract boolean canGo();
	}

	private class BackwardButton extends DirectionButton {

		static private final long serialVersionUID = -1;

		protected void doButtonThing() {

			modelFrameSelections.goBack();
		}

		BackwardButton() {

			super(BACKWARD_BUTTON_LABEL);
		}

		boolean canGo() {

			return modelFrameSelections.canGoBack();
		}
	}

	private class ForwardButton extends DirectionButton {

		static private final long serialVersionUID = -1;

		protected void doButtonThing() {

			modelFrameSelections.goForward();
		}

		ForwardButton() {

			super(FORWARD_BUTTON_LABEL);
		}

		boolean canGo() {

			return modelFrameSelections.canGoForward();
		}
	}

	NavigationPanel(ModelFrameSelections modelFrameSelections) {

		this.modelFrameSelections = modelFrameSelections;

		add(new BackwardButton());
		add(new ForwardButton());
	}
}
